Re: Jump timing (the discussion continues)

["Dean W. Cains" <dwc@xxxxxx>]

Hi Thomas:

I don't disagree with you, that a snapped timing belt doesn't necessarily 
result in complete disaster, because when the belt snaps, the engine stops 
as the cams have stopped.  I never said otherwise.  But if a timing chain 
is still intact, and at the same time displaced by enough to snap two 
valves, it will necessarily snap all the valves.  This must happen because 
the engine is still turning, and the valves are still timed the same as 
they were, in relationship to one another, as determined by the cam 
lobes.  And, as Alan (owner  of the Spider in question) mentioned, he was 
driving his Spider at 100mph when the problem started, and continued to 
drive it, after the chain allegedly jumped.  That's how I'm certain his 
timing chain didn't jump.

Considering that the Spider had just been messed with by one mechanic, 
before the incident, and then another after the incident, it may be hard to 
know who did what, but my money is still on a loose vacuum hose, cracked 
distributor cap, bad ignition wire, loose injector plug, etc, and unless 
mechanic #2 screwed with the timing chain tensioner, those valves are just 
as intact now as they were before the car started running badly.

Unfortunately, I'll bet our fellow Alfa owner is not being taken care of as 
best he might be, and that was my concern.  He never replied to my direct 
email, or asked for assistance from the Digest to get another opinion about 
his Spider via personal inspection.  I'm not implying Alan had any 
obligation to reply, either, but he asked for our help.  Later, he did send 
a somewhat frantic request to the Digest for all kinds of specs regarding 
valve spring tension, valve clearances, etc., and that can't be a good 
sign.  None of those specs in question were of any consequence, anyway, and 
any Alfa mechanic wouldn't be asking for them, even if they were 
necessary.  He'd already know what to do, and wouldn't be looking for help 
from the car's owner.

Maybe I'm just a little over-protective of fellow Alfa owners that aren't 
experienced enough to take care of their own cars, as perhaps you and I 
are, but I think that's part of the deal in owning an Alfa, and I'm always 
more than willing to help any other Alfa owner.  It's like our own 
Hippocratic oath, where we swear to first do no harm and to share our 
knowledge about Alfa's with other Alfa owners.  Maybe the sequence of 
events didn't occur exactly as they were described by Alan, but in any 
case, something is wrong with the whole story.

I'm certainly glad to hear that your V6 engine survived its bout with a 
semi-toothless timing belt, and I'm not sure if/how you got the impression 
I'd feel otherwise.  Anyway, comparing the Alfa V6 to the I4 is like apples 
to oranges, or pecorino romano to parmagiano reggiano, if you prefer.

Regards,

Dean
'74 & '87 Spider Veloce's

At 07:44 AM 4/19/2003, you wrote:

> Date: Fri, 18 Apr 2003 21:11:23 EDT
> From: Iopsycheng@domain.elided
> Subject: Re: alfa-digest V9 #429
>
> Dean and John,
> I've got a news flash for you two... I'm not defending the mechanic who
> claimed an Alfa spider jumped the timing chain but I can tell you from
> personal experience that losing the timing belt in a 2.5 liter GTV-6 at 6250
> RPM will NOT necessarily destroy the entire engine. At 53,000 miles I
> stripped 50% of the cogs off of the timing belt while charging up an on ramp.
> I had just hit the rev limiter when the failure took place... The engine died
> immediately. I tore the heads down and sent them off to Sperry for an
> upgrade. As a professional machinist I have access to any precision measuring
> and testing equipment imaginable and I and a qualified NDT inspector. The
> only damage to the engine was three bent intake valves and a minor nick in
> the top of #4 piston. ALL other reciprocating and rotating parts were
> undamaged! I reassembled the engine using the original pistons, liners,
> pushrods, connecting rods and cam followers. Currently the engine has over
> 100,000 miles and you can ask anyone in the Mid-Atlantic Alfa Club's
> Tidewater branch or Georgian Gaz and they will tell you my GTV-6 runs just
> fine and will still turn to the limit any and every time I so desire. It does
> now wear a mechanical belt tensioner and the belt gets swapped yearly...
> Cheaper that way!
> Thomas Gonnella
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